The invention relates generally to an electrical connector pair, whose individual plug elements are made of a base material coated with tin or with a tin alloy. More particularly, the invention relates to coatings for such plug elements that enhance the operating characteristics of the plug elements.
Ideally, one should be able to repeatably mate and separate the electrical connector pair or plug connector with negligible plug-in forces, and without any significant change in the contact resistance. Plug connectors are usually comprised of sockets (or adapter plugs) and plugs, which are manufactured from metal bands (strips) through deformation. The base material used for the connectors is given a complete or partial surface coating before being deformed. This coating is meant to protect the base material from attack by corrosion as well as improve soldering capability.
In general, all metals and metal alloys customarily used in electrical applications are suited for use as the base material. Copper and copper alloys are particularly preferred for use as the base material. It is known to coat the band of the base material either galvanically with tin, or to apply tin or a tin-lead alloy to the metal band in a molten bath.
The coated metal band, and the plug connector manufactured from it, must meet the following requirements:
(1) consistently low contact resistance; PA1 (2) optimally low plug-in and tensile (pulling) forces; PA1 (3) high plug-in and pulling frequencies; PA1 (4) high level of corrosion resistance; PA1 (5) sufficiently high contact force; PA1 (6) good workability;
There remains a need for electrical connector pairs that provide sufficient levels of such qualities, particularly with respect to low plug-in (i.e., insertion) and tensile (pulling out) forces.